Known examples of this type of conventional dielectric ceramic composition include a dielectric ceramic composition for high frequencies proposed by the applicant of the present invention in Patent Document 1. The dielectric ceramic composition includes a ceramic composition represented by the general formula xMgO-ySiO2 (wherein x and y represents the percent by weight of respective elements and satisfy 40≦x≦85, 15≦y≦60, and x+y=100) and one or both of a material (Ba source) converted to a barium oxide by sintering and a material (Sr source) converted to a strontium oxide by sintering. The Ba source and the Sr source are added at a total content of 0.3 to 3.0% by weight in terms of BaCO3 and SrCO3.
Patent Document 2 discloses a multilayer ceramic capacitor including two or more types of ceramic dielectric layers having different dielectric characteristics. In the multilayer ceramic capacitor, dielectric layers and conductor layers are alternately laminated, and the conductor layer is disposed on at least one of the surfaces of each dielectric layer. In addition, a glass material paste layer is formed over the entire surface of each dielectric layer, including the conductor layer, to form an adhesive layer including the glass material paste layer and the conductor layer. The conductor layer of the adhesive layer is used for forming a predetermined pattern, and a ceramic thin sheet is bonded to one or both of the glass material paste layer and the conductor layer. The conductor layers are composed of a conductor paste or conductive adhesive, and the dielectric layers are formed by laminating at least one each of two or more dielectric ceramic thin sheets separately formed and having different dielectric characteristics.
Patent Document 3 discloses a dielectric ceramic composition for high frequencies composed of forsterite, zinc titanate, and calcium titanate. The dielectric ceramic composition has a composition represented by the general formula xMg2SiO4-yZn2TiO4-zCaTiO3 (wherein x, y, and z are shown by mol % and satisfy 21<x<88, 4<y<71, 4≦z≦14, and x+y+z=100).
Patent Document 1: Japanese Patent No. 3446249
Patent Document 2: Japanese Examined Patent Application Publication No. 6-48666
Patent Document 3: Japanese Unexamined Patent Application Publication No. 2004-131320